As discussed in U.S. Pat. No. 5,792,811, the fixed glass windows (such as the windshield) of a modern automobile are bonded to the painted steel body of the automobile using an adhesive (such as a urethane adhesive). The periphery of the window is usually already coated with black cosmetic paint called the “enamel band”. A primer is applied to the enamel band along the area of the window to be bonded to the automobile to improve the strength of the bond between the enamel band and the cured adhesive.
The area of the enamel band to be primed can be controlled using a mechanical means, such as an edge guide or a template. Alternatively, the area of the enamel band to be primed can be indicated by a pattern printed or otherwise marked on the enamel band. If the primer is applied robotically, then the robot can be programmed to apply the primer to the desired area of the enamel band.
The primer is often not visually detectable after it has been applied to the enamel band. Thus, it is difficult to determine if an area of the enamel band requiring the primer has been properly primed. It would be an advance in the art of applying an adhesion primer to the enamel band of such a window if a process were developed that indicated the area to be primed and then confirmed that such area had been primed.